let sum = (x, y) => x + y
// console.log(sum(4, 5))

const obj = {
  name:"aqie",
  age:18,
  skill:{
    name:'code',
    year: 11
  }
}
Object.freeze(obj) // 对象不会改变,只冻结一层
Object.freeze(obj.skill)
// obj.skill.year = 12
// console.log(obj)

// import './1.ts'
//import './chapter7/7-1'
import './chapter8/8-2'
